Yes, in the very base of it, that's true. However, its in the armors and the broken arms that the issue of the head comes in... (also, although they are almost the same size in your image, they still are not in many areas such as the arms, legs, and shoulders, where Fenris's black outline is clearly just a bit larger to appear outside of the white mesh of the PC. that tiny difference can have a huge effect on a person's perception of things...)
I did a pretty quick, not completely accurate I admit, breakdown...

Ahem...now first is the shoulder to head ratio. Normally, shoulders should be the same length of the head turned sideways. As you can see, both the PC and Fenris sport shorter shoulders then their head size, however, Fenris is just slightly larger and the shoulder pads of his armor (which he has at all times) makes up for half the missing size. Meanwhile, Solas is about around the correct, well proportioned size (as far as the human body).
In this breakdown of head to shoulder, Solas is most proportionate. Fenris second. The PC, third.
Next is the chest size and the space between the chest and the ears. Again, Solas has the broadest chest with the most spacing, followed by Fenris, and lastely by the PC again.
Finally, there's the hip to chest angle. For both Fenris and Solas, the turnout is mostly straight, again thanks to armor. The PC is angled just slightly more inward, though this picture is not the best for comparison.
In the end, they are similar while Solas is far more human. However, the PC is just slightly less broad and more awkward at points compared to fenris. (Again, Fenris's armor made up for a lot here.)